[tech] Coke Machine Buttons

[Bob Adamson]

Today we discovered that the old bug with the coke machine is even worse 
with the new dispense. For those of you who don't know, the coke machine 
can only do one thing at a time - if you're pressing a button while 
sending it data, it will drop a drink. This bug was hard to exploit with 
the old dispense, since it only queried the coke machine when a drink was 
being dispensed.

The old dispense occasionally corrupted the coke machine contents, so 
OpenDispense2 actually "fixes" the machine every 20 seconds by sending it 
'd7' to query the status. It turns out this meant you could dispense a 
drink just by holding down a button for about 20 seconds (I don't think we 
gave many drinks away for free for what it's worth). This problem has been 
remedied by simply removing the microswitches from behind the buttons. 
It's not an ideal solution, but it works for now. It will be a harder to 
manually dispense now, so we really need to find a better long-term 
solution.

Bob Adamson
UCC President

|"Bureaucracy is a challenge to the be conquered with a righteous        |
|attitude, an intolerance for stupidity, and a bulldozer when necessary" |
| ---Peter's Laws                                                        |